hnperlai ylcaddny of Sdoicci af Pelcrshnr^h. 277 



hypotheses, cijunlly cchbraled by the names of their authors, 

 have been t'ornud on this sul)ject: tliat of Newton, which 

 makes hiiht to couaist in material emanations from lumi- 

 nous bodies ; and that of Kuler, according to whom it arises 

 from the vibrations of a ])articuhir elastic fluid wliiehare 

 produced bv the action of hmiinous bodies. The founder 

 of the modern chemistry, the iUustrious Lavoi'jier, has given 

 a third hypothesis in regard to hght ; which is, that there 

 exists in nature a pccnTiar matter which is \he productive 

 cause of the sensation denoted under the name of light ; 

 that the matter of light is subject to cliemical affinities, in 

 consequence of which it is susceptible of combining with 

 other bodies, of iixing itself in them, of being disengaged 

 from tiicm, and of producing in them sensible modiiica- 

 lions ; that by the effect of its great affinity for oxygen it 

 redu(.es it, with the concurrence of caloric, to that aeriform 

 stute under which it enters into the composiiion of atmo- 

 fjphcric air; and that the fire manifested in the combustion 

 of bodies results from the decomposition of the oxygen gas 

 of the atmospheric air operated bv the combustible accord- 

 ing to the laws of affinitv, in virtue of which tlie oxygen, 

 which forms the base of this gas, lieing absorbed by the 

 burnino- bodv, the caloric and matter of light become free and 

 arc disengaged. However uncertain and subject to diflicuUies 

 may still appear the existence of a matter of light, and the 

 reality of its affinities, on which the illustrious author of 

 the hypothesis expresses himself with a reserve worthy of 

 so great a searcher into nature, it is however beyond all 

 doubt that this ingenious idea, w hich is not entirely desti- 

 tute of support from experience, exhibits a kind of research 

 highlv interesting to the progress of tiatural philosophy. If" 

 there i;xists a matter of light, if it be subject to chenjical 

 affinities, and diffused around us, it may, by the combina- 

 tions into which it enters with other bodies, have a striking 

 JnflueHcc on them and on several natural phainomena. The 

 advancement of our knowledge in resrard to this matter 

 would consequently furnish us with results v/hieh, by giving 

 us further information in regard to the secret springs ot na- 

 ture, nn'ght, perhaps, throw new light on a number of 

 its operations. In consideration of these reasons the Im- 

 perial Academy has thought it would be advantageous to 

 the progress of science tt) propose publicly a prize of 300 

 rul)lcs, which will be adjudged to the philosopher who shall 

 make, and communicate to it, " the most instructive series 

 of new experiments on light considered as matter; o\\ the 

 properties which he nuy be authorized to ascribe to it j on 

 S3 the 



